A cover for a sunken enclosure includes a mounting part for mounting it to a sunken enclosure with which it is used such that the cover is movable between a closed position in which it closes an open top of the enclosure and is substantially level with a surface intersected by the open top, and an open position in which it is displaced from the surface and exposes an internal area of the enclosure, and in which the cover includes an antenna for transmitting and receiving radio waves.